leaky planked boat. ok. can you careen it somewhere to look closer at the involved plank and make sure it is only a part of a plank or mebbe only a missing bit of caulk, vs dry rot and teredo worms.
i would NOT use a pick on it under any conditions. best afloat not on bottom.
i have always been able to locate dry rot well without a pick , but with fingernails. much more kind to the hull you are destroying with an overzealous pick.
some splash zone, aka marine tex (look online-- it will give you at least what to look for in your area) will work until you can save the dough for plank replacement and whatever else the boat will need. keep an eye on that part of boat.

My first boat was clinker construction. 2nd winter, I was ashore for some months rather than in a mud berth and 1 plank opened-up slightly, just above the waterline. All was well until I was hard over on port tack, then I got the spurt of water inside.
Blackwater caulking was advised by the old oystermen - put her in a mud berth and let the mud do the sealing. Yes, it was on the river Blackwater
I tried to refasten, but it would not do it. The mud did though - it allowed the moisture to take-up the gap.
Being underwater, the pressure may prevent a proper seal, but more than anything else, you need to careen and check the area for the wee beasties that feed there

My first boat was clinker construction. 2nd winter, I was ashore for some months rather than in a mud berth and 1 plank opened-up slightly, just above the waterline. All was well until I was hard over on port tack, then I got the spurt of water inside.
Blackwater caulking was advised by the old oystermen - put her in a mud berth and let the mud do the sealing. Yes, it was on the river Blackwater
I tried to refasten, but it would not do it. The mud did though - it allowed the moisture to take-up the gap.
Being underwater, the pressure may prevent a proper seal, but more than anything else, you need to careen and check the area for the wee beasties that feed there

Think the oystermen were pulling your chain. Worst thing you can do. Mud sets up a lot of organisms to eat at your wooden hull. A big no no. Clean dry wood or wood that is only saturated in salt water is the way to go. Being cheap is death to wooden hulls. Up here in Maine we always advise to haul and fix if there is a leak of any size after the hull has swelled. Anything else is sheer stupidity.

Think the oystermen were pulling your chain. Worst thing you can do. Mud sets up a lot of organisms to eat at your wooden hull. A big no no. Clean dry wood or wood that is only saturated in salt water is the way to go. Being cheap is death to wooden hulls. Up here in Maine we always advise to haul and fix if there is a leak of any size after the hull has swelled. Anything else is sheer stupidity.

Far from it Reed1!
As I stated, the leak was planks above the waterline, the mud held the moisture there long enough for the planks to swell. Sheer genius - it did not need any "fixing" all it needed was time.
I would always check underwater leaks properly.

Our boat is western red cedar strip planks, epoxy and glass inside and out. Some of the epoxy and glass delaminated from the rudder, and inside 3 weeks, teredo worm had got in. This occurred somewhere between Qld. and Pittwater. From this experience, I fear for your boat if there is access clear through a plank, therefore, I hope you can get it hauled out or sealed up post haste.

Do zeehag's fingernail trick, and if you find the pinhole that way, fill it with the sawdust, or Splash Zone, if you can't haul and fix. Your boatwright may be used to leaky wood boats, but if sea organisms can get into that pinhole and commence chewing, that is just a bad deal. It all depends on whether it's just a pinhole that filling up with splash zone, will cut off the water supply for the teredos, or not. In our case, the teredo eventually exited the hole, and dried out there on the rudder while the boat was hauled, but that took a few days on the hard.

Whoever came up with the idea of using a pick on a wood boat should be keel-hauled. That's like saying "lets make a pinhole where there wasn't one before."

The OP hasn't stated whether the shipwright thought it was from a seam or a plank. I'd trust the shpwright -- but we dive on our boat (even in cold waters) to inspect and clean. If you don't know what's going on, then dive, get on a tide grid, or do a haulout to figure it out. We own a wood boat, and we pay attention to every little thing it does -- from a weep here or a leak there we know what is happening and why. Hopefully you, too, will soon have every little nuance well understood.

PS many people do patch over an area of water ingress--with an OUTSIDE patch. a bit of wood (even plywood), some bedding (your choice) and a couple wood screws (or through bolted if access from the inside is available) to hold it in place until the haulout. Airtools work under water. Not for long term use--just until the haulout. If it is a seam, that's a different matter though but your shipwright can advise.

__________________

"The only noble thing a man can do with money is to build a schooner." Robert Louis Stevenson

[QUOTE=Djarraluda;2181994]Far from it Reed1!
As I stated, the leak was planks above the waterline, the mud held the moisture there long enough for the planks to swell. Sheer genius - it did not need any "fixing" all it needed was time.

I was responding to the OP and thought you were suggesting plowing his boat into mud to fix a bottom leak. That would have been sheer stupidity, as other posters have pointed out. Still stand by the bad mud idea. All you are doing is fostering dry rot.

Sawdust and splash zone compound are for emergencyrepairs, so you can get the boat to the haulout yard. There you can discover what prevents your vessel from being seaworthy and make necessary and suitable repairs.

__________________1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design

teredo worms work very very fast. my now gone mahogany boarding ladder was worm riddled in one season --then patricia took it along with the fittings away forever--so i get to build another--
there was a wood mariner 31 in barra lagoon with teredo worm construction. i think the worms were keeping out the ingress of water-- he had to careen it in sandbar to fix.
whenever there is a water leaky hull, it needs to be at least careened and inspected well to ensure no further spots requiring replacment or recaulking or repair.
my uncle with hes antique beauty we learned on had been hit, thankfully above water line by a planing little speed boat. the temporary repair he effected while sailing lasted over 5 years.
make sure you seal boat tight before splashing. let it sit in slings for 3 days to expand the wood so it actually doesnt leak.
btw--a knife is same as a pick. use finger nail to keep rotty boat from sinking. helpful hint--you can SMELL rot, so i f you smell grannys attic when you board a boat-- either charge for repairs or run like hell.

You state that the vessel is PLANKED, but not carvel, so what is the method ?, trying to stop the leak from the inside is a problem, due to the water pressure, the sawdust is a temporary fix, the problem is locating the leak in the water, if you can shove a wire from the inside thru, then you can locate it and do a patch of some sort.